1. Field of the Invention
The present invention relates to a method and an installation for producing slabs in a continuous casting plant. The continuous casting plant includes a strand guiding means arranged following the casting mold and divided into segments which each is composed of a two-part segment frame whose frame parts are braced together by means of hydraulic cylinders, wherein pairs of oppositely located rollers for supporting and for conveying the solidifying cast strand are mounted in the frame parts, and wherein at least one of these rollers, i.e., the drive roller, is pressed with a defined adjusting force against the cast strand for transmitting the conveying forces.
2. Description of the Related Art
DE 19 63 146 C1 discloses a plant for producing slabs in which the parts of the frame of the strand guiding means with their oppositely located rollers are combined to form segments, wherein the segment frames are composed of two yoke frames supporting the rollers and the yoke frames are adjustable through tension anchors and spacer pieces to the casting size.
In conventional strand guiding stands using the segment configuration of the type described in DE 19 63 146 C1, in curved installations in which the cast strand is guided from the vertical casting direction into the horizontal rolling direction, the upper frame and the lower frame of each segment are braced relative to each other by means of four hydraulic cylinders which connect the frames and are arranged at the corners outside of the travel path of the cast strand. The adjustment to different strand thicknesses is effected by means of spacer pieces against which the frame parts are pressed.
Because of this type of construction, a change of the distance between the rollers during the casting process is not possible.
In order to eliminate this deficiency, DE 43 06 853 C2 proposes to arrange a hydraulic plunger cylinder between the spacer pieces and the respective side frame part and to dimension the angular piston of this hydraulic plunger cylinder in such a way that in the pressureless state the hydraulic plunger cylinder fixes the segment parts to that distance between the rollers which corresponds to the desired strand thickness. This measure makes it possible to adjust the guide rollers in three defined positions.
Since in these known guiding strands the hydraulic cylinders press the segment frame parts against the spacer pieces and, thus, cannot act directly on the rollers which support and guide the cast strand, at least one of these rollers, i.e., the drive roller, is pressed by separate hydraulic adjusting cylinders (usually two adjusting cylinders for each drive roller) against the cast strand with the adjusting force required for the transmission for the strand conveying forces. This is usually effected in the middle of the segment, so that, depending on the introduced force, bending of the respective segment side frame may occur.